What others have said, if you’re going to be staying near the stadium then stay at the hotels at or near LAX, but not in Inglewood.

Highly recommend staying at the Hilton next to the LA Kings training facility in El Segundo, or at any of the hotels on that block (Mariposa Ave). There’s a train station right next to the Hilton, and you can use that train (C line) to get to SoFi Stadium via the gameday shuttles.

Go Metro on Game Day - LA Metro

I believe there’s also a Hyatt in El Segundo right next to the Douglas station.

You can take a shuttle from LAX that will connect you to the C line.

LAX Official Site | Traffic and Ground Transportation (flylax.com)

From the C line you can connect to the A line. The A line goes to LA Union Station/Pasadena, or to Long Beach. Unfortunately the K line is not fully completed yet, so if you want to go to Santa Monica/Venice you’re probably going to have to take an Uber up to the nearest K line stop in Inglewood, then take that up to the train that will get you to Santa Monica. Do not recommend having to rely on Uber to get around LA as Uber is expensive here, and the LA metro region is massive.

As for where to meet up with Rams fans before the game, try going to the tailgate lot at the stadium. There’s also a casino that’s practically on property, so that’s another place people go to pregame.